A door hinge is a mechanical bearing that connects a door to a frame, allowing it to rotate along a horizontal axis. The hinge is typically made of metal and consists of two plates, one mounted on the door and the other on the frame, that are connected by a pin, also known as a hinge pin, which allows the door to rotate. The hinge plates typically have knuckle, leaf and pin, which form the hinge mechanism. The hinge is designed to provide a pivot point for the door to rotate around and also to support the weight of the door. There are different types of hinges, each with its own unique design and application such as butt hinges, continuous hinges, spring hinges, pivot hinges, and more.
The history of door hinges dates back to ancient times, where simple wooden hinges were used in Egypt and Greece. In the Middle Ages, iron hinges were introduced in Europe, providing greater security than wooden ones. The Industrial Revolution brought mass production of door hinges, making them more affordable. During the 19th century, brass, bronze, and steel hinges were developed and became popular. Today, door hinges come in a wide range of materials and finishes, with different designs and mechanisms to suit different types of doors and usage.
Door hinges can sag due to a variety of reasons, including improper installation, a lack of maintenance, or wear and tear. The most common cause of sagging hinges is a loose or worn hinge pin, which can cause the door to lose its proper alignment and sag. Additionally, the door or door frame may have warped or twisted over time, or if the door is too heavy for the hinges, it will cause them to sag over time as well.
Continuous hinges, also known as piano hinges, are considered to be the strongest type of door hinge. They are made of one long piece of metal and are mounted continuously along the length of the door, providing more support and stability than traditional hinges. They are typically used in heavy-duty applications such as industrial and commercial doors, and are known for their durability and strength.
Door hinges are typically mounted on the interior of the door for security reasons. When the hinges are on the inside, it makes it much harder for someone to remove the door from the outside, as the hinges are not visible and cannot be tampered with. This makes it harder for intruders to break in, and provides an extra layer of security for the building. Additionally, mounting the hinges on the inside can also help protect the hinges from the elements and prolong their lifespan.